It is very similar to what you are asking for: a 3D Locator constrained to a surface.

On Friday, 7 December 2012 01:37:09 UTC-5, tk52 wrote:> Howdy folks.>>>> Could someone please help smash thru my current brick wall?>>>> I generate 3D surfaces from medical anatomy files (".off" files). I would like to be able to scroll the mouse over the surface & click to set an interactive point on the surface, & have the program be able to read the {x,y,z} coordinates of the new point.>>>> Can anyone point me in the right direction.>>>> Thanks very much.>>>> Tom